This central and southern Appalachian diploid (2n = 24) has been reported from Ky. by Parks & Hardin (1963), FNA 26, W and others. However, these reports may just be based on misidentifications, and the extent of its westerm range in general remains uncertain..The species was not recognized until 1963; GC (1952) had stated under americanum: "Races with yellow and with brown-red anthers exist and some students of the genus have suspected that two species are included." E. umbilicatum is reported to differ from rostratum and americanum as follows (FNA 26, W; B Sorrie, pers. comm.): petals lacking auricles at base (versus present), medium yellow (versus richer yellow to golden); capsule and ovary usually becoming distinctly indented at apex (versus not so); mature capsules usually reclining on ground, with the apex downward (versus usually held well above ground); stolons 0-1 per bulb (versus 1-5); anthers usually lavender, brown, cinnamon, or purple (versus usually yellow). Flowers appear 1-2 weeks earlier than americanum where they cooccur in N.Car., and umbilicatum tends to occur on more acid soils (B. Sorrie at https://auth1.dpr.ncparks.gov/flora). However, there has been little critical review of these characters. The name umbilicatum has been applied to some rather inadequate Ky. colls. of albidum (from CALL & MARS at MUR) and of americanum (from MENI in M; POWE at NCU). Parks & Hardin also cited a coll. from CHRI (Hardin #383 at US) but they did not map it; the coll. has not been relocated. L. Pounds reported umbilicatum in 1986 to the National Park Service, based on a coll. of americanum from the Cumberland Gap area in HARL (TENN). There are also disjunct western records from c. Tenn. (Ch) and n. Ala. (K)..